Field of the Invention
The present invention generally relates to apparatus for protecting horticultural and agricultural plots from small animals and, more particularly, to an installation for repelling birds. This installation causes bird flight from orchards, gardens, vineyards and the like, so that birds feeding habits are interrupted.
An activity of significant magnitude is the growing of fruit and berries. Trees growing fruit such as apples, pears, peaches, cherries and the like are presently grown in large orchards. Also, small fruit such as raspberries, strawberries, blueberries and the like are presently grown in bushes over extensive surfaces.
In the past, various types of devices and installations have been used in attempts to scare birds away from trees and bushes bearing fruit.
It has been proposed to utilize a loud noise so as to scare birds into flying from a crop field. Such a noise is usually provided by an air gun using a combustible gas. The air gun ignites the combustible gas at predetermined time intervals. However, due to the air gun""s widespread use, the birds become accustomed to the noise and the scarring effect is gradually diminished. Also, such method of producing a loud noise is generally rejected by the surrounding neighborhood.
Also, it has been proposed to protect horticultural and agricultural plots against attack by bird flocks with nets or similar protective webbing. This approach is limited, since the cost of acquiring, installing and operating a system according to this method would be prohibitive, especially for large plots.
In view of the impracticability of the loud noise method and the substantial cost associated with the building and operating of the net covering system, farmers have generally turned to the tactic of scarring birds away by using repelling installations. Thus, German Patent No. 1,281,741, dated Oct. 31, 1968 and granted to Bachli for an xe2x80x9cINSTALLATION FOR PROTECTING AGRICULTURAL CROPS FROM BIRDSxe2x80x9d describes several embodiments wherein use is made of carrying lines provided with scarring features. In a first type of embodiments, each carrying line is engaged in a limited, alternative movement with respect to its initial position. In a second type of embodiment, carrying lines cover large surfaces and are actuated by endless cables across the whole length of a plot. Bachli""s embodiments have important shortcomings. In the first type of embodiments the protected surface is limited, while in the second type of embodiment the use of pulleys, around which an endless cable is actuated by a reversible electric motor via a mechanical transmission, presents a major technical disadvantage. It is common knowledge, that any flexible transmission of power, such as flat and V-belts or chains can be used only for limited distances, while the surfaces protected from birds imply long distances. U.S. Pat. No. 4,109,605, dated August 29 and granted to Bachli for a xe2x80x9cSCARECROW SYSTEMxe2x80x9d discloses an installation using a main towline carrying deterrent devices. The main towline is supported by wire or rope-held pulleys, secured to movably poles attached to the soil, and is actuated by a drive assembly that imparts a reciprocating movement. A main disadvantage of this installation resides in the fact that the crop surface remains not protected, only corners and border surfaces being protected.
Following the foregoing situation, there is a need for an installation for repelling birds that overcomes the disadvantages of the prior art.
Therefore, an objective of the present invention is to develop a reliable and efficient installation.
Another objective of the present invention is to provide a well-engineered installation so that it is simple to assemble and operate, and comprises components that generally wear evenly.
Yet another objective of the present invention is to provide a relatively inexpensive installation.
The present invention is predicated on the conviction that the use of one line, stretched drive guy rope in the present installation solves the long distance transmission of mechanical power. Furthermore, the use of a pair of carrying lines, provided with scarring elements, one carrying line simultaneously traveling in a direction opposite to the other carrying line, greatly enhances the efficiency of the present installation.
Broadly describing, the present installation comprises a unilinear drive assembly incorporating a stretched drive guy rope provided at each end with a swivel joint, a driven rotating element and at least one driving pulley, the former and the latter being firmly secured to the stretched drive guy rope. At least one driven pulley is opposed to the driving pulley and has a centerline situated in a plan passing through the midsection of the latter. At least one endless cable is tensioned between the driving and driven pulleys and has an upper path and a lower path. A pair of stretched guide ropes, essentially parallel to the endless cable is used. Each one of the stretched guide ropes is perpendicularly disposed to the stretched drive guy rope and extends from the ends of the latter. At least one carrying line is perpendicularly disposed with respect to the pair of stretched guide ropes. One carrying lines is attached to the upper path, while another is attached to the lower path, each end of each carrying line being slidably engaged with an adjoining one of the pair of stretched guy guide ropes. An actuating assembly includes a reversible electric motor connected to a reduction gear drive that is provided with an output drive shaft. On the latter, a drive wheel is securely fastened and transmits, via a mechanical transmission, a torsional moment to the driven wheel. The endless cable is provided with devices for triggering a change of direction of the reversible motor. Those devices are attached to the upper and lower paths at opposite positions, adjacent the driven pulley and the driven pulley, and act when the upper and the lower path, alternatively, at an end of their traveling paths come close to the driving pulley.
In one aspect of this invention, the installation for repelling birds further comprises devices for tension adjusting, secured outwardly from each swivel joint and from both ends of each stretched guide ropes. The devices for tension adjusting are adapted to be attached to posts anchored to the ground.
In another aspect of this invention, the installation for repelling birds further comprises at least one tensioning spring secured inwardly from at least one of the swivel joints of the unilinear stretched drive guy rope and inwardly from at least one of the devices for tension adjusting of each of the stretched guide ropes.